Geometry Practice Test 1

Question : 31 of 40

Marks: +1, -0

The radius of two concentric circles is 9 cm and 15 cm. If the chord of the greater circle is a tangent to the smaller circle, then the length of that chord is:

24 cm
12 cm
30 cm
18 cm

Validate

Solution:

By Pythagoras theorem,

(OB)^2

(OP)^2 + (PB)^2

(15)^2

(9)^2 + (PB)^2

225 - 81 =

(PB)^2

144 =

(PB)^2

PB = 12 cm
AB = 24 cm

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